The present disclosure relates generally to a medical fluid delivery system and in particular to a dialysis system. U.S. Patent No. 5,350,357, the entire contents of which are incorporated herein by reference, shows a peritoneal dialysis machine 10 having housing 12. Housing 12 holds a bag heater module 14 located under a bag heating plate 16. Housing 12 further encloses a pneumatic actuator module 20. Pneumatic actuator module 20 incorporates a cassette holder 22 that holds a disposable dialysis cassette (not illustrated) and a liquid shutoff assembly 24. Machine housing 12 further encloses a source 30 of pneumatic pressure and an associated pneumatic pressure distribution module 40, which links the pressure source 30 with the actuator module 20. Pressure distribution module 40 stores positive pressure in reservoir 32 and negative pressure in reservoir 34. Machine housing 12 also encloses an AC power supply module 36 and a back-up DC battery power supply module 38 to power machine 10.
Tubing 42 connects pneumatic valves located on pressure distribution module 40 to the machine components that operate using pneumatic pressure. Slots 44 in the side of the pressure distribution module 40 accommodate the passage of the tubing 42. In particular, tubing 42 runs from pressure distribution module 40 to actuator module 20, where the tubing connects to components such as a cassette sealing bladder (not illustrated), an occluder bladder for liquid shutoff assembly 24 and to pump and valve actuators that control the application of positive and negative pressure to different areas of the disposable cassette.
Each of the tubes 42 has to be disconnected individually to remove either pressure distribution module 40 to actuator module 20 from machine 10. Tubes 42 are not easy to disconnect. Tubing 42 often stretches and becomes unusable when pulled off the barbed fittings connected to pressure distribution module 40. The barbed fittings themselves can be damaged if an attempt is made to cut tubes 42 off the fittings.
FIG. 2 shows pressure distribution module 40 exploded. Pressure distribution module 40 includes a printed circuit board 46 which is carried on stand-off pins 48 atop the pressure distribution module. Pressure transducers 50 mounted on printed circuit board 46 of module 40 sense through associated sensing tubes 52 pneumatic pressure conditions present at various points along the air conduction channels (not illustrated) within pressure distribution module 40. Pressure transducers 50 and/or the solder joint that connect the pressure transducers to the printed circuit board 46 can be damaged if an attempt is made to disconnect the tubes between the manifold and the pressure transducers.
Attempts to detach the tubing from actuator module 20 also encounter problems. FIG. 3 shows a cassette interface 26, which is located inside actuator module 20. T-fittings 28 connect the tubing 42 to the ports of the valve actuators and pump actuators. Thus to remove actuator module 20 from pressure distribution module 40, cassette interface 26 has to be accessed first and then T-fittings 28 have to be removed from cassette interface 26.
A need therefore exists for a dialysis machine that is more readily repaired and maintained.